The present invention provides a method, instrumentation and implants to treat pathology of the spine, typically degenerative disc disease or degenerative joint disease. The methods and instrumentation can be used to treat the spine for other pathologies such as fractures, tumor, etc., with or without implants. This invention is related to the disclosure in U.S. Pat. No. 6,589,281, which is fully incorporated by reference herein.
Degenerative spine pathology has been recently treated with some method of fusion of parts of the spine to stop motion and reduce pain. There are many known methods of spine fusion. Pedicle screws have been favored by some surgeons to increase the success of the fusion surgery which relies on the formation of a success of the fusion surgery which relies on the formation of a solid bone mass from the bone of the vertebral bodies and bone graft. Spinal cages have also had some success in improving fusion rates.
Fusion sacrifices motion for pain. Stresses that are usually accommodated at the fused level are transmitted or moved to adjacent vertebrae and are felt to accelerate degenerative joint disease at levels above and below the fusion site.
Spinal disc replacements have been recently developed, using UHMWPE and cobalt-chrome (CoCr). Other material combinations are also used. Currently spinal disc replacements are investigational devices in the U.S. There are disc designs for cervical and lumbar pathology. The different regions of the spine require different engineering and surgical considerations. This has led to multiple spine disc products that vary in forms, applications and materials. The surgical approach for the cervical and lumbar spine disc replacements has been typically via an anterior approach that can be complicated and hazardous. The anterior approach removes additional portions of the disc annulus fibrosus to provide exposure to insert the artificial disc, compromising the structural integrity of the spine disc mechanics. Some approaches for spine disc replacement require the assistance of a general surgeon to help with the exposure.